Math Is Fun Forum

haiying

Guest

10n – n = 10(n – 1) + (10 – n)

can someone help me to use the basic properties and algebra to prove that 10a –a = 10(a – 1) + (10 – a)

and show me what property did you use at each step .

THANK YOUUUUUUUU:)

S.M

Member

Registered: 2011-02-16

Posts: 7

Re: 10n – n = 10(n – 1) + (10 – n)

hmmmmmmmmmm
10(a-1)+(10-a)=
10a-10+10-a=
10a-a

haiying

Guest

Re: 10n – n = 10(n – 1) + (10 – n)

hmmmmmmmmmm
10(a-1)+(10-a)=
10a-10+10-a=
10a-a

i need the opposite way ... how 1a - a = 10 (a - 1) + (10 -a):o

S.M

Member

Registered: 2011-02-16

Posts: 7

Re: 10n – n = 10(n – 1) + (10 – n)

hmmmmmmmmmm
10(a-1)+(10-a)=
10a-10+10-a=
10a-a

i need the opposite way ... how 1a - a = 10 (a - 1) + (10 -a):o

hmmmmmmmmmm
ok
see this one
------------------
10a-a=                                     
we add +10-10
10a-a+10-10=
we arrange them
10a-10+10-a=
10(a-1)+(10-a)